﻿art. 
  5 
  THE 
  GEXUS 
  PENTACRINUS 
  — 
  SPRINGER 
  3 
  

  

  complications 
  relative 
  to 
  it, 
  the 
  reader 
  should 
  consult 
  Bather's 
  paper 
  

   on 
  " 
  Pentacrinus, 
  a 
  Name 
  and 
  a 
  History.'" 
  4 
  

  

  The 
  name 
  is 
  involved 
  in 
  considerable 
  confusion, 
  and 
  students 
  are 
  

   apt 
  to 
  be 
  misled 
  by 
  the 
  manner 
  of 
  its 
  use 
  in 
  the 
  literature 
  at 
  certain 
  

   periods. 
  The 
  two 
  principal 
  species 
  were 
  described 
  by 
  J. 
  S. 
  Miller 
  

   in 
  his 
  Natural 
  History 
  of 
  the 
  Crinoidea. 
  1821, 
  as 
  Pentacrinus 
  briar- 
  

   em 
  (p. 
  56, 
  pis. 
  1 
  and 
  2) 
  from 
  the 
  lower 
  Lias, 
  and 
  P. 
  subangularis 
  

   (p. 
  59. 
  pis. 
  1 
  and 
  2) 
  from 
  the 
  middle 
  or 
  upper 
  Lias. 
  It 
  is 
  evident 
  

   from 
  Miller's 
  descriptions 
  that 
  he 
  had 
  as 
  types 
  specimens 
  from 
  the 
  

   t} 
  T 
  pical 
  localities 
  : 
  P. 
  briareus 
  from 
  Lyme-Regis, 
  Dorsetshire, 
  Eng- 
  

   land, 
  and 
  P. 
  subangularis 
  from 
  the 
  black 
  slate 
  in 
  Wurtemburg, 
  

   German}^. 
  He 
  credits 
  subangularis 
  also 
  to 
  Lyme-llegis, 
  and 
  de 
  

   Loriol 
  refers 
  a 
  specimen 
  from 
  France 
  to 
  that 
  species; 
  while 
  Quen- 
  

   stedt 
  describes 
  several 
  varieties 
  of 
  P. 
  briareus 
  from 
  Wurtemburg 
  

   localities; 
  but 
  it 
  is 
  open 
  to 
  question 
  whether 
  the 
  two 
  forms 
  are 
  not 
  

   chiefly 
  confined 
  in 
  Europe 
  to 
  their 
  respective 
  localities 
  and 
  horizons. 
  

   There 
  is 
  some 
  confusion 
  in 
  the 
  descriptions 
  as 
  to 
  horizon; 
  subangu- 
  

   laris 
  is 
  credited 
  to 
  both 
  the 
  middle 
  and 
  upper 
  Lias, 
  and 
  briareus 
  to 
  

   upper 
  and 
  lower. 
  

  

  These 
  two 
  most 
  common 
  species 
  in 
  the 
  Lias 
  of 
  England 
  and 
  Ger- 
  

   many 
  are 
  extremely 
  abundant, 
  often 
  composing 
  entire 
  strata, 
  in 
  

   which 
  their 
  remains 
  are 
  beautifully 
  preserved, 
  furnishing 
  most 
  

   striking 
  specimens, 
  which 
  are 
  to 
  be 
  seen 
  in 
  nearly 
  all 
  museums. 
  

  

  The 
  name 
  Pentacrinus 
  as 
  employed 
  by 
  Miller 
  included 
  two 
  types 
  : 
  

   1, 
  in 
  which 
  the 
  radials 
  project 
  downward 
  over 
  the 
  proximal 
  eol- 
  

   umnals, 
  and 
  the 
  arms 
  are 
  heterotomous 
  ; 
  and 
  2, 
  in 
  which 
  the 
  radials 
  

   do 
  not 
  so 
  project, 
  and 
  the 
  arms 
  are 
  dichotomous. 
  The 
  name 
  was 
  

   also 
  applied 
  to 
  the 
  earlier 
  described 
  stalked 
  crinoids 
  of 
  the 
  present 
  

   seas, 
  such 
  as 
  P. 
  caput-medusae, 
  P. 
  mulleri, 
  P. 
  wyville-thomsoni, 
  P. 
  

   decorus, 
  etc. 
  Then 
  the 
  Austins 
  in 
  1848 
  proposed 
  to 
  separate 
  the 
  

   species 
  of 
  type 
  No. 
  1 
  under 
  a 
  new 
  genus, 
  Extracrinus, 
  leaving 
  only 
  

   those 
  of 
  No. 
  2 
  under 
  the 
  original 
  name. 
  This 
  course 
  was 
  followed 
  

   by 
  de 
  Loriol 
  5 
  and 
  by 
  P. 
  H. 
  Carpenter 
  in 
  the 
  Challenger 
  Report 
  on 
  

   the 
  Stalked 
  Crinoids, 
  and 
  the 
  names 
  were 
  applied 
  by 
  them 
  accord- 
  

   ingly. 
  

  

  Later 
  on 
  it 
  was 
  discovered 
  that 
  the 
  Pentacrinus 
  briareus 
  of 
  Miller, 
  

   which 
  had 
  been 
  illustrated 
  under 
  the 
  name 
  of 
  the 
  Briarean 
  Penta- 
  

   crinite 
  by 
  Parkinson 
  in 
  1808 
  6 
  and 
  of 
  which 
  Miller's 
  name 
  had 
  been 
  

   copied 
  into 
  treatises 
  and 
  textbooks 
  generally, 
  7 
  was 
  the 
  identical 
  

   species 
  which 
  had 
  been 
  described 
  by 
  Blumenbach 
  in 
  1802 
  from 
  a 
  

   specimen 
  from 
  Dorsetshire 
  as 
  Encrinites 
  fossilis, 
  and 
  as 
  Pentacrin- 
  

  

  i 
  Natural 
  Science, 
  vol. 
  12, 
  1898, 
  p. 
  254. 
  

  

  : 
  Crinoides 
  de 
  la 
  France, 
  vol. 
  2, 
  1868, 
  p. 
  385. 
  

  

  e 
  Org. 
  Rems., 
  vol. 
  2, 
  p. 
  248. 
  

  

  ' 
  Dana's 
  Manual 
  of 
  Geology, 
  ed. 
  4, 
  p. 
  778. 
  

  

  